The present invention relates to methods of separating gases and, more particularly to the methods of separating gases using microchannel devices and ionic liquid absorbents.
The Losey paper describes a contacting method for a gas and a liquid reaction system but does not suggest absorption-desorption as a potential unit operation. Matthew W. Losey et al, “Microfabricated Multiphase Packed-Bed Reactors: Characterization of Mass Transfer and Reactions,” Ind. Eng. Chem. Res. 2001, 40, 2555-2562. “Solubilities and Thermodynamic Properties of Gases in the Ionic Liquid 1-n-Butyl-3-methylimidazolium Hexafluorophosphate”, Anthony, J., Maginn, E., and Brennecke, J., J. Phys. Chem B 2002, 106, 7315-7320, describes one example of an ionic liquid that suggests a single stage separation of methane and nitrogen are possible. Both of these articles are incorporated by reference.
The use of wicks or capillary structures for thin film is described in U.S. Pat. Nos. 7,051,540 and 6,875,247, which are incorporated by reference. Surface features for multiphase processing are discussed in U.S. Patent Application Publication Nos. 2007/0085227, 2007/0017633, and 2006/0073080, which are incorporated by reference.
Gas separations are discussed in U.S. Pat. Nos. 6,579,343 and 6,623,659, U.S. Patent Application Publication No. 2006/0251558, and PCT Published Application No. WO 02/34863, which are incorporated by reference.
Options for the absorption and desorption of SO2 from flue gas independently or in conjunction with CO2 absorption and desorption have been considered by a few researchers (Wu, W., Han, B., Gao, H., Liu, Z., Jiang, T., Huang, J., “Desulfurization of flue gas: SO2 absorption by an ionic liquid,” Angew. Chem. Int. Ed., vol. 43, pp. 2415-2417, 2004; Anderson, J. L., Dixon, J. K, Maginn, E. J., Brennecke, J. F., “Measurement of SO2 solubility in ionic liquids,” The Journal of Physical Chemistry B, vol. 110, no. 31, pp. 15059-15062, 2006, each of which is incorporated by reference). Problems with typical wet and dry absorption techniques, including large water requirements and post-absorption treatment, dust formation and sorbent poisoning, plugging, or deactivation have led to consideration of ionic liquids as potential sorbents.
Foam flow is discussed in Stemmet, C. P., Jongmans, J. N., van der Schaaf, J., Kuster, B. F. M., Schouten, J. C., “Hydrodynamics of gas-liquid counter-current flow in solid foam packings,” Chemical Engineering Science, 60, 6422-6429, 2005; Stemmet, C. P., van der Schaaf, J., Kuster, B. F. M., Schouten, J. C., “Solid Foam Packings for Multiphase Reactors—Modeling of Liquid Holdup and Mass Transfer,” Trans. ChemE, Part A, Chemical Engineering Research and Design, 84 (A12), 1134-1141, 2006; and Stemmet, C. P., Meeuwse, M., van der Schaaf, J., Kuster, B. F. M., Schouten, J. C., “Gas-liquid mass transfer and axial dispersion in solid foam packings,” Chemical Engineering Science, 62, 5444-5450, 2007. The aforementioned references are incorporated herein by reference.